THE SPERM WHALES, GIANT AND PYGMY. 129 
In order now to exhibit the relative importance of the 
characters and their subordination, it may simply be stated 
that the chief, or at least most salient peculiarities in the form 
and relation of the bones are those exhibited by the supraoc- 
cipital in combination with the parietals, and also those pre- 
sented by the frontals. In these respects, the sperm-whales 
stand alone among the cetaceans, while the Ziphiids, to 
Which they are most nearly allied, and with which they agree 
in the costal cartilages, the form of the pterygoids, etc., 
resemble the Delphinids in the development of those bones. 
4. Differences among Physeterids. Having now pretty 
carefully passed in review the common characters of the 
Physeterids, we may now enter on an examination of the 
subdivisions which are indieated by a similar course of study. 
After a detailed investigation of all known forms it is found 
that they may readily be grouped into two divisions which 
are separated from each other by many striking peculiarities. 
One of these is represented by the large species; the other 
by small ones ; for the former, has been retained by the best 
naturalists the Linnean name Physeter; for the latter, was 
first proposed the Grayan name Kogia, a barbarous designa- 
tion which has by some been superseded by Huphysetes. In 
order to exhibit at once the contrast between the two forms, 
and to facilitate comparison, we append the characters in 
parallel columns. 
PHYSETER. 
orm massive, with the head 
very large, oblong in profile and 
truncated at the front; eyes very 
small, very low, and near the angle 
of the mouth; blow-hole anterior, 
and at or near the edge of the trun- 
cated snout. 
Form delphinoid, with the head 
conical, the snout being attenuated 
than the angle of the mouth; blow- 
hole at the forehead. 
Dorsal fin represented by a hump. 
Cervical vertebre differentiated 
into an atlas and a combination of 
the second to seventh anchylosed 
and fused together. 
AMER. NATURALIST, VOL. IV. 
Dorsal fin falcate. 
Cervical vertebræ all united by 
anchylosis. 
